Preformed pavement marking materials (sometimes known as pavement marking tapes), such as short or long distance lane striping, stop bars, and pedestrian lane markings at intersections are used as traffic control markings to guide travelers using roadways or other traffic-bearing surfaces. Typically, preformed pavement marking materials comprise a wear-resistant top layer overlying a conformable base layer and an adhesive layer (e.g., a pressure-sensitive adhesive or contact cement).
Generally, pavement marking tapes are white, yellow, or black. The yellow and white pavement marking tapes provide contrast with the roadway (or traffic-bearing surface) material. Black pavement marking tapes are typically useful in construction zones to cover existing yellow or white markings.
Although the yellow and white pavement marking tapes generally have good daytime visibility or conspicuity, there are roadway materials and regions of the country where the visibility of these markings can be enhanced. White pavement marking tapes may readily "blend" with the roadway color, negatively affecting visibility. For example, white pavement markings on concrete roadways tend to blend with the roadway color. In the southern part of the United States (e.g., Florida), the asphalt roadway surface "bleaches" after prolonged exposure to the sun. Here, white pavement marking tapes may "blend" with the asphalt roadway color.
One method of enhancing daytime visibility is to place a contrasting color (such as black) longitudinally between the white or yellow skip-lines.
A second method involves placing a contrasting color (e.g., black) alongside the white or yellow pavement marking tape to form a composite. Composite pavement marking tapes comprising strips of a pavement marking material of one color longitudinally spliced together with strips of a pavement marking material of a second color to form a multi-colored pavement marking tape are currently available commercially. One such self-contrasting pavement marking tape is a black and white tape, 380-5 Stamark.TM. Contrast Tape, available from Minnesota Mining and Manufacturing Company ("3M"), St. Paul, Minn. In a composite pavement marking tape construction, each single color pavement marking tape is separately coated onto a backing and slit to the desired width of the strip, or "zone." The pavement marking strips of various colors are then spliced together, typically with filament tape, to form the composite multi-colored pavement marking tape.
The current available multi-colored pavement marking tapes require first coating and slitting each color strip of pavement marking tape, and then splicing the three strips together. This manufacturing process is labor intensive and time consuming, and therefore costly. Additionally, pavement marking tapes made by this manufacturing process are susceptible to coming apart at the splice region and/or loosening from the pavement at the splice region. These tapes independently perform and weather on each side of the splice as three separate products. These durability deficiencies are particularly problematic in high traffic skip areas.
The need exists for multi-colored retroreflective articles such as pavement marking tapes, which exhibit greater durability and greater ease of manufacture. Such multi-colored pavement markings preferably provide excellent daytime contrast while maintaining nighttime retroreflectivity.